Aqueous dyeing of acid-dyeable polyamide fibers using yellow-to-orange disazo dyes

ABSTRACT

IN AN AQUEOUS PROCESS FOR DYEING TEXTILE MATERIALS COMPRISED OF POLYAMIDES, PARTICULARLY DEEP-DYEABLE POLYAMIDES AND POLYAMIDE STYLING YARNS AND FIBERS, AT A PH OF 3-7 AND AT A TEMPERATURE UP TO THE BOIL, IN THE PRESENCE OF DYES AND DYEING ASSITANTS, THE IMPROVEMENT OF USING YELLOW-TO-ORANGE DISAZO DYES OF THE STRUCTURE   (2-HO,3-R1,5-R-PHENYL)-N=N-B-N=N-A   WHEREIN   A= (R2)N,(M-O3S-)PHENYL, OR (M-O3S-)NAPHTHYL   THE SO3M GROUP IN THE LATTER STRUCTURE BEING SUBSTITUTED IN EITHER AROMATIC RING OF THE MAPHTHALENE NUCLEUS; R2=METHYL, METHOXY, NHCOCH3, CL OR BR; N=3, 1 OR 2; M=H, ALKALI METAL OR AMMONIUM CATION;   B= (2-Y,5-Y-1,4-PHENYLENE), OR 1,4-NAPHTHYLENE   X AND Y=H, C1-2 ALKYL OR C1-2 ALKOXY; R=C1-5ALKYL, -NHCOC1-4ALKYL, OR , WHEN X(OR BOTH X AND Y) IS A SUBSTITUENT OTHER THAN H, CL OR BR; AND R1=H OR C1-5 ALKYL.

United States Patent 3,676,050 AQUEOUS DYEING F AClD-DYEABLE POLY- AMIDEFIBERS USING YELLOW-TO-ORANGE DISAZO DYES Daniel S. James, Hockessin,Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del.No Drawing. Filed Jan. 21, 1969, Ser. No. 792,783 Int. Cl. C09]: 31/04U.S. Cl. 8-41 B 11 Claims ABSTRACT OF THE DISCLOSURE In an aqueousprocess for dyeing textile materials comprised of polyamides,particularly deep-dyeable polyamides and polyamide styling yarns andfibers, at a pH of 3-7 and at a temperature up to the boil, in thepresence of dyes and dyeing assistants, the improvement of usingyellow-to-orange disazo dyes of the structure wherein (R z) n the $0 Mgroup in the latter structure being substituted in either aromatic ringof the naphthalene nucleus; R =methyl, methoxy, NHCOCH C1 or Br',

n=0, 1 or 2;

M=H, alkali metal or ammonium cation;

X and Y=H, C alkyl or C alkoxy;

R=C alkyl, NHCOC alkyl, or, when X (or both X and Y) is a substituentother than H, C1 or Br; and

This invention relates to dyeing of polyamide textile materials,particularly deep-dyeable polyamides and polyarnide styling yarn andfibers as hereinafter defined. More specifically it relates to animproved dyeing process employing specific yellow-to-orange, disazo,acid dyes.

As is true in any area of intense commercial activity, some significantmodifications have recently evolved in the dyeing of nylon, andparticularly in the dyeing of nylon with disazo dyes as described inU.S. Pat. 3,485,814. Another example illustrating the rapid developmentsin the field of nylon dyeing, particularly nylon carpets, is describedin an article in the American Dyestuff Reporter by J. A. Brooks et al.,pp. 68-72, Nov. 20, 1967. This article further describes the use ofnylon fibers having different aflinities for acid dyes to obtain stylingeffects in piece dyeing.

For a dye to be commercially attractive for dyeing nylon (i.e.,synthetic polyamides), the dye must certainly have afiinity for nylon,and have at least a minimum degree of lightfastness. It would bedesirable, moreover, for nylon dyes to possess the quality known astranfer; that is,

3,676,050 Patented July 11, 1972 the ability to equilibrate effectivelybetween dyed and undyed filaments. In the particular application ofstyling carpets, due to the carpet construction and placement of thedifferential dyeing nylon fibers, transfer is of lesser importance thanwhen the carpet to be dyed is constructed from yarn of uniformdyeability.

The generally accepted mechanism for dyeing nylon with acid dyes,normally carried out at a ptl-I of 4-6, may be summarized by thefollowing equations:

69 9 nylon-NR2 H 0 3 nylonNH H20 nylon-NHa O S-dye These equationsillustrate that the dye sites are the free amine end groups. These freeamine end groups, being basic, may be protonated in acidic solution toyield positively-charged ammonium groups. In this positivelychargedform, they serve as sites, by interionic attraction, for the anionic dyemolecules.

Thus, if nylons are to be prepared with varying degrees of dyeability,this may be accomplished by controlling the number of free amine ends inthe nylon polymer, i.e., by varying the ratio of diamine to dicarboxylicacid monomer in the preparation of the polymer. Thus nylon fibers arenow available which contain various amounts of free amine groups andthus varying degrees of dyeability with acid dyes, e.g.,

(A) Fibers containing about 5-25 gram-equivalents of free aminegroups/10 grams of polymer which are only lightly dyeable with aciddyes;

(B) Fibers containing about 25-55 gram-equivalents of free aminegroups/.10 grams of polymer which may be dyed with acid dyes to a mediumdepth; and

(C) Fibers containing about 55-120 gram-equivalents of free aminegroups/1O grams of polymer which are heavily dyeable with acid dyes (seefor example Ben, U.S. Pat. No. 3,078,248).

An unusual problem has arisen in dyeing type (C) fibers (i.e., thedeep-dyeables), especially in dyeing styling yarns and fibers as areformed in carpeting, i.e., carpeting containing each of the three aboveacid-dyeable fibers and basic (cationic)-dyeable nylon fibers as taught,e.g., in Magat, U.S. Pat. No. 3,184,436. Surprisingly, it has been foundthat when deep-dyeing nylon is present, certain dyes normally useful fordyeing nylon carpets (as those in the aforementioned U.S. Pat.3,485,814, exhibit a serious deficiency. This deficiency manifestsitself as a shade change and decrease in dye lightfastness. Toillustrate, some available yellow dyes yield lightand mediumyellowshades on the lightand medium-dyeable nylons with good lightfastness. Ondeep-dyeable nylon, however, when a heavy-yellow shade would be desiredand expected, the actual dyeing is not on tone, but much redder in shadeand the lightfastness markedly decreased. This shade-shift and poorlightfastness is unacceptable to the trade.

The reason some dyes exhibit a shade change on deepdyeable nylon isassumed to be due to the basic conditions of the fiber. In forming nylonpolymer from diamines and dicarboxylic acids, e.g., hexamethylenediamine and adipic acid, both free amino and free carboxyl groups arepredicted as possible end groups. Now, with both lightand medium-dyeablenylon, as described above, the number of free carboxylic acid groupsapparently exceeds the number of free amine groups.

With deep-dyeable nylon, however, it appears that the number of freeamine groups exceeds the number of free carboxylic acid groups; thus,the pH of deep-dyeable nylon is apparently above 7. Moreover, the fiberbasicity of deep-dyeable nylon appears suflicient to remove a Now, inthe presence of deep-dyeable, basic nylon, apparently the phenate formof the dye is formed by removal of a proton, as follows: 10

To the extent that the above reaction occurs, the dyes shade will bealtered since a phenate dye will have a diiferent electronicdistribution and absorption spectrum than a dye with an nonionizedphenolic group. Indeed, it would appear that when the phenate form ofthe dye is formed, the shade shifts from yellow or orange towards redand dye lightfastness decreases. It should also be pointed out that onlya minor shade shift, that is to say, only a few phenate dye moleculesneed be formed, to give an unacceptable and noticeable shade change andpoorer lightfastness.

As the above equation indicates, undesirable shade changes might beexpected with certain dyes in the presence of other basic agents. In thetrade, certain finishing treatments for woven and knitted nylon textilegoods, and certain scouring procedures for dyed carpets, apparentlycontain amines which are substantive to nylon. When these amines areabsorbed by nylon, since they are basic, they may also produce thedeleterious shade change and reduced lightfastncss with some acid dyes.

Therefore, the objectives of this invention include providing dyes fordyeing nylons without significant shade shifts; providing dyes fordyeing nylons with adequate afiinity for and lightfastness on nylonfibers; and providing dyes for dyeing nylon which are unaffected byconventional basic finishing or scouring procedures.

BRIEF SUMMARY OF THE INVENTION These objectives and others are fulfilledby providing, in an aqueous process for dyeing polyamide textiles,particularly deep-dyeable nylons containing about 55-120 (usually 80-90)gram equivalents of free amine groups/ grams of polymer, at a pH of 3-7and at a temperature up to the boil, in the presence of acid dyes anddyeing assistants, the improvement consisting of using, as said aciddyes, yellow-to-orange disazo dyes of the following structure: 5

r AN=NB-N=NC wherein (112M A: or Q R =inethy1, methoxy, NHQOCH C1 or Br;

4 n=0, 1 or 2 (where the R groups may be the same or different); M=H,alkali metal or ammonium cation;

X and Y=H, C alkyl or C alkoxy;

R=C alkyl, --NHC0C alkyl, or, when X (or both X and Y) is a substituentother than H, C1 or Br; and

As a preferred embodiment, the above improvement is applied to theprocess of dyeing textile materials comprised of polyamide styling yarnsor fibers, especially those containing bulked continuous filamentdeep-dyeable polyamides, wherein the material is immersed for about10-180 minutes in an aqueous dye bath maintained at a pH of 3-7 and atabout 70-100 C.; which bath contains acid and basic type dyes and about0.05 to 0.50% by weight of a sulfobutaine of the structure:

wherein R =an acyclic aliphatic hydrocarbon radical containing 7-17carbon atoms;

m=an integer of 0 to 3;

p=an integer of 0 to 3; and

m+p=less than 4.

CHa; a, is -11; A is NaOaS or G S O Na O C H3 I and B is C or 0-, as forexample I CH3 I SO Na DETAILED DESCRIPTION OF INVENTION It has now beenfound that, in the dyeing of polyamide textile materials, especiallystyling yarns, =fibers and carpeting containing deep-dyeable nylons,that the use of the yellow-to-orange disazo dyes as above definedsignificantly reduces the shade shifts resulting with heretoforeemployed disazo acid dyes. While the invention is not to be limited bydiscussions of the mechanisms involved, it is suggested that theimprovements attained with the subject dyes are probably due to thepositioning of the phenol hydroxyl group in a position ortho to the azolinkage where it may hydrogen bond therewith, i.e.,

thus rendering the subject dyes more resistant to the tendency to beconverted to their phenate form by the basicity of deep-dyeable nylons.

Textile materials By polyamides (or nylons) are included those syntheticlinear polycarbonamides characterized by recurring amide linkages as anintegral part of the main polymer chain such as poly(hexamethyleneadipamide), poly(hexamethylene sebacamide), poly(m-xylene adipamide),poly- (p-xylylene sebacamide), polycaprolactam and the like as well ascopolyamides. Poly(hexamethylene adipamide) constitutes the preferredpolyamide.

Polyarnides are utilized in many textile applications, specifically forpreparing woven and knitted goods, etc. Nylon has, of course, also foundgreat acceptance in the carpet market. In all the marketingpotentialities known, e.g., carpets, upholstery, hosiery, apparel,parachutes, etc., the use of differential dyeing fibers has commercialsignificance. That is, by constructing textile goods from nylon fibersof differential dyeability, appealing tone-ontone styling effects can beobtained.

For the large carpet market, bulked continuous filament (BOP) polyamidehas been widely acepted for constructing economical tufted carpets. BOPpolyamide constitutes a preferred substrate for the process of thisinvention. BCF polyamide may be prepared, i.e., jet-bulked, with the jettaught by Hallden et al. in US. Pat. No. 3,005,251.

Additional styling effects, again especially significant for the carpetmarket, are achieved in the trade by combining, with the threedifferential acid-dyeable nylon fibers discussed above, cationic-dyeablenylon. With this type of construction, obviously, dyers are permittedeven greater styling variations since multicolor dyeings can be made. Asone very simple illustration, a carpet construction may be assumed asfollows:

Repeat Repeat Pattern i Llght i Medl I Heavy i i Pattern Aid DyeableBasic Dyeable Since the four yarns are available, a carpet manufacturermight tuft the yarns, either on jute or a synthetic backing aspolypropylene. Now acid dyes are available which are attracted only tothe acid-dyeable fibers, panels, or rows. A dyer might, for example,elect a yellow acid dye for the acid-dyeablc portions. If done on oursimple pattern above, strips or rows of light-, medium-, and heavyyellowwould be produced, with negligible color on the basic-dyeable nylon.Now, if the dyer so desired, he could simultaneously add selectedcationic (basic) dyes and obtain an entirely different shade on thebasic-dyeable nylon, e.g. blue, green, red, black, etc. Such availablebasic dyes which may be applied include Sevron" Yellow 3RL (OI. BasicYellow 15); Sevron Yelloiw MFW (C.I. Basic Yellow 31); Sevron Orange CL(Cl. Basic Orange 25); Sevron Red L (Cl. Basic Red 17); Sevron Blue B(C.I. Basic Blue 2.1); Sevron Blue 2G (Cl. Basic Blue 22); and the like.

This simple illustration hopefully conveys the principle of differentialdyeing and its importance for opening up an almost infinite number ofstyling effects (i.e., toneon-tone, dyed-undyed, mutlicolored) availablefor nylon in textile applications. Basic-dyeable nylons have beendescribed in US. Pat. No. 3,184,436. Nylon, heavily-dyeable with aciddyes, has been described in US. Pat. No. 3,078,248.

'In the hypothetical pattern discussed above, if it is assumed that wehave used, as our yellow dye, a dye of we would have been disappointedsince a deep-yellow shade would not have been obtained; indeed, thatportion would be red with poor dye light fastness. The potentialattendant problems are obvious, i.e. prospects of achieving anunappealing, perhaps even clashing, dyed textile, etc. By using the dyesand the process of this invention, these unsatisfactory results may besubstantially avoided.

It is to be understood that a broad class of polyamides may be employedas substrate in this invention. Several polyamides have been describedby Ben in US. 3,078,248, for example polyhexamethylene adipamide,poly(2-methylhexamethylene oxamide), polycaprolactam, the polymerderived from m-xylylene diamine and adipic acid, etc. Polyhexarnethyleneadipamide appropriately modified with various antistatic additives, U.V.screeners, etc., and polyamides prepared from4,4-bis-aminocyclohexylmethane and dodecanedioic acid may also be dyedby the appropriate dyeing procedures.

The dyeing process is aqueous and may conveniently be carried out usingper part of textile material, 20 to parts of water without effect on theprocess efficiency. The amount of dye assistant (e.g., disodiumdodecyldiphenyl ether disulfonate) used may be varied from 0.5% to 4.0%by weight, although .5 to 2% is the preferred amount. Lesser amounts areinsufficient to insure satisfactory leveling and streak coverage.Amounts greater than 4% may lead to poor exhaust from the dyebath andconsequent economic loss, and also has caused a diminution oflightfastness. Dyeings may be carried out at a pH from 3 to 7, butexperience has shown the most favorable results with nylon fiberscontaining up to about 100 gram-equivalents of free amine groups/ 10grams of polymer occurs with the pH at 6 to 7. Higher pH causes poorexhaust, the dye tending to stay in the bath rather than attachingitself to the nylon. On the other hand, with nylon fibers containingmore than 100 gram-equivalents of free amine groups/10 grams of polymer,it is most desirable that the pH of the dye-bath not be allowed to riseabove about 6 for at least the greater portion of, and particularly atthe termination of, the dyeing process. In dyeing suchultra-deep-dyeable nylons (i.e., 100-120 gram-equivalents) at a pH muchgreater than about 6, while there is no problem with lightfastness, thesubject dyes will tend to undergo dulling shade changes. This tendencyto undergo a dulling shade change of pI-Is much greater than about 6occurs, in spite of the greater shade stability of the dyes of theinstant invention over those containing a hydroxyl group para to the azolinkage, because there is a limit to the basicity of the substrate(unless the pH is kept below about 6) beyond which even the subject dyestend to undergo a drilling shade change.

While the temperature may be up to the boil, the optimum temperature forthe dyeing process is 95 C. to 100 (3., most test dyeings being carriedout at 98 C. Lower temperatures extend the time required and also givepoor exhaust.

In the above process, an alkaline detergent prescour may have also beenperformed to remove finishing oils, dirt, etc. Moreover, frequently anonionic surfactant, the condensation product of a C alcohol with 10moles of ethylene oxide, is coemployed as dyeing assistant. Theconcentrations effective vary from approximately 0.25 to 2%, with 0.5%being a preferred concentration, The requisite acidic pH is usuallyattained by using acetic acid and phosphate buffers, as mono'sodiumphosphate. Also, in lieu of the anionic dyeing assistants above, othersdisclosed in US. Pats. 2,081,876 and 2,854,477 may be employed. Finally,conventional metal sequestering agents and antifoam agents may be added,the sequestering agents being especially preferred when X is alkoxy inthe disazo dyes. Versene (ethylenediaminetetraacetic acid tetrasodiumsalt) constitutes a preferred sequestering agent.

The above process is one which promotes optimum dye transfer, i.e.,equilibration between dyed and un-dyed nylon. It would be expected toyield an essentially equidepth of shade even across the entire face of a15 ft. width carpet.

The subject processes may of course also be used in the absence ofdeep-dyeing nylon. The basic dying procedures described herein are, ofcourse, well-known in the art, as described in the various citedreferences.

In dyeing styling yarns and fibers (i.e., those containing both acidandbasic-dyeable nylons) to obtain contrasting multicolor carpets, a bleachscour of the nylon is preferred as the first step. This aqueous scour,in a weight ratio of generally about 20-40: 1, includes approximately 4%sodium perborate, approximately 1/ 5 trisodium phosphate, andapproximately of the betaine described below. The bath temperature israised to approximately 160 F. and held there approximately 15 minutes.The bleach-scour bath is then discarded and the carpet rinsed with warmwater; the carpet is then ready for dyeing.

The dyeing process may be successfully carried out with dyebaths havingpH values of from 3 to 7, however the most favored pH is 6.0 to 6.2. Atthis value satisfactory exhaust of both acid type and basic type dyes isattained. Either lower or higher pH may lead to poorer exhaust and lessthen optimum constrast.

The sulfobetaine dyeing assistant may be used in amounts as low as .05of the weight of fiber being dyed, the best results being obtained with.2% to 3%. Amounts of dyeing assistant larger than .5 of the weightfiber dyed have led to staining and less eifective reserve of thenon-dyed fibers.

-It is very important that dyeing be carried out at temperatures above70 C., the best results being obtained at temperatures near the boil (95-100 0.). Lower temperatures will give inferior exhaust, staining of theundyed fibers and poor contrast.

The sulfobetaines used in the process of this invention may be preparedfrom commercially available tertiary amines having one fatty aliphatichydrocarbon group (derived from various fatty sources having mainly from8 to 18 carbon atoms) and 2- polyoxyethylene groups attached to thenitrogen as in the following general formula:

where R is an acyclic aliphatic hydrocarbon having 7 to 17 carbon atomsand m and p are integers of from 0 to 3 but the sum of m and p is nomore than 3.

8 Methods of preparing both sulfobetaines and their precursors aredescribed in U.S Pat. 3,280,179.

The sulfobetaines used in the process have the structure:

wherein R is an acyclic aliphatic hydrocarbon radical of from 7 to 17carbon atoms, in is from 0 to 3, p is from 0 to 3 and the sum of m and pis no more than 3. Its functions are to prevent precipitation ofcationic-anionic dye complexes, to promote leveling of both specieswithout suppressing buildup, and to minimize cross staining.

The bleach scouring process is also known as described more fully in thedefensive disclosure of Robbins, Ser. No. 634,477 dated Apr. 29, 1969(861 0.6. 1355).

Finally, using the above described processes with any type of nylontextile, dyeing is usually followed by conventional rinse and dryingsteps. Moreover, especially in the carpet area, conventional finishing,drying, latexing, and double backing application may be performed bycustomary means.

It is to be understood that the dyeing procedures of this invention maybe performed in conventional equipment. Thus, carpeting is usually dyedin becks; upholstery is usually dyed in jigs; accent on throw rugs areusually dyed in paddle machines.

The recently developed continuous dyeing of carpets employs differentialdyeing yarns, and thus is also benefited by the subject invention,References to this new technique are found in Melliand Textilberichte,48, 415-448 (April 1967).

The recent art teaches that continuous carpet dyeing is related to piecedyeing in that it is an aqueous dyeing but (a) at very low bath ratios,5:1 instead of 30:1 to 50:1, and (b) that the rate of fixation is muchfaster because temperatures near the boil are attained more quickly in asteamer than in heating up a beck.

Dyes.The disazo, acid dyes applicable by the previously describedprocesses to deep-dyeable nylon which fulfill the objectives of thisinvention, are characterized by possessing, in the final coupler, aphenolic hydroxyl ortho to the azo linkage. Coupling only into the orthoposition is a consequence of using, as final couplers, selectedparasubstituted phenols. The structure of the dyes is as follows:

wherein A, B, R and R are as defined above.

Some of the dyes, falling within the above generic formula, are old,having been described in French Pat, No. 1,201,549, as intermediates forsubsequent metallization to yield metallized, acid dyes.

The preparation of the dyes useful in this invention is essentially thesame as that described in the above French patent. That is, anaminoaryl-sulfonic acid, A, is diazotized and coupled to an aromaticamine, B, to yield 9 an aminoazo intermediate. Finally, the aminoazointermediate is diazotized and coupled to the final coupler, apara-substituted phenol.

Since most of the intermediate monoazo compounds are readily available,the actual preparattion of the disazo dye often is complete in one step.For example, the preparation of a preferred dye useful in this inventioninvolves only the following:

The synthesis of the preceding disazo, acid dye would involve thefollowing steps:

The coupler may be prepared by adding 30% caustic soda (105 parts) to5000 parts of water and adjusting the temperature to 25 :1 C. Then, withagitation, 284 parts of p-cresol and 50 parts of soda ash are added;complete solution occurs. The coupling solution is stirred until thediazo is ready; when the diazo is ready, the coupler solution is cooledto 10:2 C.

The preparation of the diazo is initiated by adding 4-aminoazobenzene-4'-sodium sulfonate (715 parts) to 4000 parts of water,stirring until a smooth slurry is obtained, followed by the addition ofsodium nitrite (182 parts). The temperature is held at 32:1 C.

In another vessel, hydrochloric acid (262 parts) is dissolved in water(5500 parts) and the temperature adjusted to 32:1 C. Then, the sodiumnitrite-aminoazobenzene sulfonate slurry is added with agitation to theacid solution over a period of 25:5 minutes; the temperature is allowedto rise. After stirring at 35:1 C. for 30:5 minutes to complete thediazotization, excess nitrite is destroyed with sulfamic acid and thediazo solution cooled to 10:2 C.

Coupling is effected by adding the above diazo, with strong agitation,to the p-eresol coupler solution over a period of 40:5 minutes at 10:2C. The product (the disazo dye) forms as a thick orange brownprecipitate. The product is isolated by allowing the reaction mixture towarm to 25 C., filtering the product, and washing the dye with a minimumof water. The dye may be dried at any convenient temperature up to 100C.

The dry crude dye may be standardized by finely grinding the dye withBlancol (the sodium salt of a sulfonated naphthalene-formaldehydecondensate) or preferably with a mixture of dextrin and trisodiumphosphate.

Other aminoazo compounds readily available, and thus useful in a processsimilar to the above, include m- (p-aminophenylazo) benzenesulfonie acidand m-(4- amino-3-methoxyphenylazo) benzene sulfonic acid.

All of the dyes useful in the present invention, including the above,can be prepared as described in French Pat. 1,201,549. That is, ANH isdiazotized and coupled to BNH then the intermediate aminoazo compound,AN=NBNH is further diazotized and coupled to the selected phenols. Thefollowing 10 compounds are suitable for A-NHz, B-NH and coupler:

A-NH Compounds:

aM SIOaM OCH:

NHz, N Hz, NH:

| l S 03M 8 OzM ('31 (3111 ISOaM SIOZM CH NH: and NH2 wherein M=I-I,alkali metal or ammonium cation.

B-NH Compounds:

OCH; OCH;

i ONH: and

l I a NHCOCH; NHCOC H CHa-C-CHa When X or X and Y are permissiblesubstituents other than H, particularly alkoxy, the final coupler mayalso be selected from p-chlorophenol and p-bromophenol.

Disazo dyes prepared from the above do not exhibit the strong red shifton dark-dyeable nylon as do the isomeric p-hydroxyl substituted dyessuch as the following:

S O Na and (I) C Ha 3 OaNa The subject disazo dyes yieldyellow-to-orange shades on polyamides which fulfill the objectives ofthis invention. It is to be understod that the subject dyes may be usedeither alone, to form single shades, or in combination with other acid,disperse, metallized, and/or cationic dyes to yield mixed shades,tone-on-tone, multicolored, etc. dyeings. That is, the presence of otherdyes or customarily used dyebath additives do not interfere with thesubject dyes fulfilling the objectives of this invention.

The acid dyes prepared according to the examples are shown in the formof their sodium sulfonates. It will be understood that the dyes of thisinvention may also be prepared and used in their free acid form or astheir alkali metal or ammonium salts. For instance, in Example 1 theNaOH and Na CO may be replaced by chemical equivalent amounts of KOH andK CO respectively, to provide the potassium sulfonate form of the dye.Similarly, the lithium sulfonate of the dyes may be prepared.

In order to obtain the dyes in the form of their free acids an aqueousslurry of the dye is made strongly acid with hydrochloric acid and thenwarmed with stirring. The insoluble acid form of the dye is thenfiltered off and washed with warm water.

The ammonium salts of the dyes may be obtained by dissolving their freesulfonic acids in aqueous ammonium hydroxide followed by salting outtheir ammonium sulfonates with ammonium chloride or ammonium sulfate.

EXAMPLES The following examples are offered to illustrate the subjectinvention and are not intended to be in limitation thereof.

(A) PREPARATION OF DYES Example 1Preparation of SO N8. Ha

Phenylazoaniline-m-sodium sulfonate (75% pure, 20 g., 0.05 mole) wasdissolved in water ml.) by warming to 40-50 C. 5 N-sodium nitrite (11.5ml., 0.057 mole) was added. The solution was added to a stirred mixtureof 10 N-hydrochloric acid (16 ml., 0.16 mole) and water (50 ml.) over aperiod of 10 minutes at 35 40 C. After holding a positive nitrite testat 3540 C. for a further /2 hour, the diazonium salt was cooled to 5-10C. by adding ice. It was then added over 10-15 minutes to a stirredsolution of p-creso-l (5.9 g., 0.055 mole) and sodium carbonate (12.5g.) in water g.) and 30% sodium hydroxide (5.5 ml., 0.055 mole) whichhad been cooled to 5-l0 C. with ice.

The product was filtered off and dried at 75 C. Thin layerchromatography (T.L.C.) was used to determine the purity of the dye. Theeluent used was butano1:acet0ne:water:ammonia=5:5: 1:2, and the plateswere coated with silica gel. Dry wt.=24 g.

Example 2-Preparation of The above dye was prepared as in Example 1, butsubstituting an equivalent weight of 4-.aminoazobenzene-4- sodiumsulfonate for phenylazoaniline-m-sodium sulfonate. The disazo dyeobtained has the following absorption characteristics: A (wavelength ofmaximum absorption)=360 111 4; absorptivity (i.e., absorbance per unitlength divided by concentration)=85.0/g.

Example 3Preparation of l SO NE The above dye was prepared as in Example1, but substituting an equivalent weight of 3-methoxy-4-aminoaz0-benzene'3-sodium sulfonate for phenylazoaniline-m-sodium sulfonate. Thespectral data are X =360 (420) m absorptivity=56.4/ g.

Example 4-Preparation of (I) C H3 $11 A) S OzNu C H: C Ha2,5-dirnethoxy-4-aminoazobenzene-3'-sulfonic acid (18 g., 94% pure, 0.05mole) was dissolved in water (100 ml.) and 30% sodium hydroxide (5 ml.,0.05 mole). 5 N- sodium nitrite mL, 0.1 mole) was added and the solutionadded over a period of 2 /2 hours to a stirred mixture of 10N-hydrochloric acid mL, 0.3 mole) and water (150 ml.) at 5055 C.Addition was carried out beneath the surface of the acid to inhibitfoaming due to decomposition of nitrous acid. After a further /2 hour,the diazo was cooled to 5-10 C. with ice. The coupling procedure was asdescribed above in Example 1.

Example 5-Dye characterization The following table provides dyeevaluation and characterization data for the dyes of Examples 1-4 and 12other dyes both within and outside the scope of this invention. The 12other dyes were prepared by comparable methods. Dyes numbered 1, 16, 6,and 11 correspond to Examples 1-4, respectively. Dyes numbered 2, 3, 8,and 13 are outside the scope of this invention and give an unacceptablered and dull shade on deep-dyeable nylon versus medium-dyeable nylon.The remaining dyes support the scope of this invention. Redness anddullness are associated with the formation of the phenate ion, withconcomitant drastic loss in dye lightfastness. The apparent brightnessand strength of the dyes of this invention (e.g., Nos. 1, 4, 6 and 7 inTable I) on deep-dyeable versus medium-dyeable nylon is probably due totheir better exhaust on the former versus the latter fiber. Theyellowness of other dyes falling under the scope of this invention(e.g., Nos. 5, 11 and 12 in Table I) on deep-dyeable vs. medium-dyeablenylon is quite acceptable, since there is no observable accompanyingloss in dye lightfastness.

TABLE I.ACID DYES FOR NYLON STYLING CARPET Shade deepdyeable vs.Lightfastmedium Trans ness ratings dyeable fer, 1 2 after 80 hrs., BCFDye No. Dye Shade 1 Exhaust 1 percent Xenon 1 a nylon 4 1 OH BrightFair-good... -45 5 3S.

orangeyellow. N=N- N=N l l S OiNa CH;

2 OH Orange- Good. 1D.

1 yellow.

l l S OaNa Cl 3 ('31 d0 Fair-good IE.

I S O Na 4 H? (3H3 d0 Good 30-35 6-4 Br 38.

I I S OaNa CH3 5 H? tl-butyl do Fair 2Y, Br.

I S OaNa t-butyl 6 0 OH; HO Orange- Good 5-4W 2 1 Br.

I brown I S O=Na CH3 7 ()CHs ()H do ..d0- 21 Br.

I S OaNa C1 8 OCH: O1 Orange- Fair-poor. 1R.

1 l yellow:

l S O Na See footnotes at end of table.

TA B111 IConti nucd Shade deepdycable vs. Lightfastmedium Transnessratnigs dyeable fer, 1 2 after 80 hrs., BCF

Dye No. Dye Shade 1 Exhaust 1 percent Xenon 1 3 nylon l 9 CH H0 CH3Orange- Good 2-1 Br.

I I l brown.

I l S O3Na CH:

10 (ROI-I H? ti-butyl -do. Fair I S OiNa t-butyl 11 (|)CH3 OH RedFair-good... 3-2W 3Y, Br, S.

Q Q -Q i i S 0311 0 CH3 CH:

12 fiJCH: OH Bed Fair 3Y, Br, 5.

l l S 03H 0 CE Cl 13 OCH; )1 Orange Poor Dull violet.

l S 03H 0 CH;

14 (30113 H? (3H Red Fair-good 3Y, Br, S.

I 1 S 0311 0 011a CH;

15 OOH; HCI) t-butyl Red Fair 3S.

\ S 0311 0 CH3 t-butyl 16 OH Bright orange- Fair-good -45 6-4YW 3S.

1 yellow.

l CH3 1 The shade, exhaust, transfer, and lightiastness ratings wereobtained on carpeting made by tufting nylon yarn onto either a jutebacking or a spunbonded, polypropylene backing. The BGF nylon yarn usedfor this is 3,700-dem'er, 204-continuous filaments, trilobal, jet-bulkedyarn, melt-spun from polymexamethylene adipamide) flake. The yarn isjet-bulked with the jet taught by Hallden et al. in U.S. Pat. No.3,005,251. The nylon is considered tonhe medium dyeable since itcontains approximately 40 gram equivalents of free amine groups/10 gramsof nylon. The dyeing procedure used was as o ows:

Thirty parts of the above carpeting (polypropylene) backing areinstalled in dyebath equipment. First, it is helpful to scour the carpetat 180 F. (82 C.) for 20-30 minutes in a bath made up of 1,000 partswater, 0.2 part of a nonionic surfactant (the condensation product of 20moles of ethylene oxide with one mole of Ora alcohol), 0.6 partconcentrated ammonium hydroxide and 0.15 part sodium hydroxide. The bathis dropped and the carpet is rinsed with clean water. A dyebath is thenmade up of 1,000 parts water, 0.85 part of dodecyldiphenyl etherdisulionie acid, disodium salt (U.S. Pat. N o. 2,081.876), 0.03 part ofthe acid dye, 0.6 part of monosodium phosphate and 0.5 part of anonionic surfactant, the condensation product of a Cir alcohol with 10moles of ethylene oxide. The pH is adjusted to 6.0 by addition of aceticacid or disodinm phosphate (whichever is necessary). The bathtemperature is raised to 210 F. (99 C.) over minutes and the dyeing iscontinued for one hour. The bath is dropped and the carpet is given awarm water rinse.

When the pH of the dyebath is adjusted to 6.5, instead of 6.0 as in thepresent example, similar results are obtained.

Any of the dyes of the present invention may be applied in this mannerto give yellow to orange shades.

In lieu of the leveling agent used in this example, others disclosed inU.S. Pats. 2,081,876 and 2,854,477, may be employed.

Wool and silk may also be dyed in fast yellow-to-orange shades by theprocess of this example.

2 Transfer is ameasure of a dyes ability to equilibrate between dyed andundyed yarn. Thus, aloop of nylon carpeting as in note 1 above is dyedwith the candidate dyes by the above procedure. Then hall the dyed loopis removed and a fresh, undyed, equal weight portion of nylon carpetingis sewed in to recreate the loop. Then, this loop goes through thedyeing cycle again, but without the addition of fresh dye. In thisprocess, some dye will enter the dyebath from the dyed goods, and thusbe available for dyeing the fresh, undyed nylon. Thus, the original dyednylon will be stripped down and the fresh nylon become dyed. Perfecttransfer or equilibriation is evidenced by a strip-down of on theoriginal dyed goods, with both the dyed and fresh, undyed nylon becomingdyed to equal depths at the end of the simulated dyeing cycle. Thus, theoptimum transfer is 50%. Usually, a transfer of 40-45% is required toachieve level dyeing over a 12-15 ft. wide commercial nylon carpet.

a The lightfastness ratings are in accordance with the A.A.T.C.C. andInternational Gray Scale (see scale under Example 7). The Xenon Arc and80 standard fading hours exposure are also in accordance with acceptedA.A.T.C.C. standards.

4 This test involves comparing the shade change on deep-dyeable nylon,i.e., containing approximately 80 gram equivalents of free aminegroups/10 grams of polycarbonamide polymer as described in U.S. Pat. No.3,078,248, versus medium-dyeable nylon, as defined in note 1. Shadechange ratings are again based upon well-known A.A.T.C.C. Gray Scalemethods. (See ratings under Example 7.)

(B) PROCESS OF DYEING in Width, prepared with the followingpoly(hexamcihylcne adipamides): Example 6 (a) Cationic-dyeable, 1300denier, such as described in U.S. Pat. No. 3,184,436; In this example,the carpet was multifiber BCF nylon (b) Medium-dyeable, 3700 denier; andyarn tufted onto a non-woven polypropylene backing. (c) Decp-dyeable,3700 denier, as described in U.S.

The carpet consisted of three bands, each one six ends Pat. No.3,078,248.

CHQCHZOH R-N-CHzCHzCHzSQ:

CHzCHzOH where R:

C16 is C monounsaturated (40% and 0.25 part of trisodium phosphate. Thetemperature was then raised to 160 F. for 15 minutes. The carpet wasrinsed in warm water at 100 F.

Dyeing.100 parts of carpet were heated for 10 minutes at 80 F. in 4000parts of water containing 0.25 part of the aforementioned sulfobetaineand sufficient monosodium phosphate to adjust the pH to 6.0-6.2. 0.1part of the dye of Example 2 was added and the dyebath temperatureraised at 23 C. per minute to 208 R, which temperature was maintainedfor 1 hour. The carpet was rinsed and dried.

The results are tabulated under Table II following Example 7.

Example 7 The process of Example 6 was repeated using 0.18 part of thefollowing dye (outside the subject invention):

1 SOaNa Table II gives the results of Examples 6 and 7:

TABLE II Liglitl'astness* (shade change) Shade on exposure to Xenon Arcdepth 80 Standard Fading Hours Shade (b) vs. Stain Ex (0) vs. (b)percent on (a) (c) (b) (a) 6 25 5 5-4B R 5 5 7 1D 25 5 2-4BR 5 5 Thenumbers and letters in the table (as Well as in Table I above)correspond to accepted A.A.T.C.C. and International Gray Scale ratingsas follows-Degree of alteration in shade and strength: Class5=Negligible or No Change; 4=Slight Changed; 3=Noticeably Changed;2=Considerably Changed; 1=Much Changed; BR=Brighter; BL=Bluer; D=Duller;G= Greener; M=Monotone; R=Redder; S=Stronger; W=Weaker; Y=Yell0wer.

NOTE.-(C) indicates deep-dyeable component; (b) indicates mediumdyeablecomponent; (21) indicates cationic (base)-dyeable component.

18 Example 8 Nylon taffeta, prepared with medium acid-dyeable poly(hexamethylene adipamide), was dyed by conventional means with the dyesof Example 2 (2.0% standardized dye, O.W.F.) and a mixture of relatedisomeric dyes. The mixture of isomeric (non-invention) dyes was used toobtain a comparable shade to Example 2, and was prepared withessentially equal weights of the following dyes (where O.W.F. indicateson weight of fiber):

SOENB [0.98% standardized dye, O.W.F.] and II. (|)CH3 I r l SOQNQ [0.96%standardized dye, O.W.FJ

Then, the shade stability of the dyed nylon tafieta to various alkalineand amine chemicals was determined. The data is shown in Table III,where the numbers and letters pertain to A.A.T.C.C. standards describedin Example 7:

TABLE III (A) Dyed with mixture (I and II, noninvention dyes) Heattreated for 15 min. at 320 F.

Soaped 1.0% 10 min. acetic Imme- One Imme- Gold at acid Treatedwithdiately day diately rinse 120 F. rinse 10% soda ash 3R 2D 2D 32D3-2D 3D 1% caustic 3D 3-2D 2D 3-2D 3-2D 3D 5% urea 5 5 5 5 5 5 5% AvitexRt. 5 3W 4R1D 2D 5-4D 2D Conc. NH'ZOHZ Wet, v.m. hlk Dry 5 5 5 5 6 5 (B)Dyed with Example =2 dye (dye of this invention) 10% soda ash- 3R 5 4D 55 5 1% caustic 3D 5 4D 5 5 5 5% urea 5 5 5 5 5 5 5% Avitex" R' 5 3 5 3D2W 3-2D Cone. NH4OH:

Wet 1 hlk Dry 5 5 5 5 5 5 *Avitex R is listed as a complex higheralkylamine comgositlop in McCutcheons Detergents and Emulsifiers, 196'7nnua The above data show that, surprisingly, the improved dyeing processof this invention yields dyed nylon goods with superior stability tovarious alkaline and amine chemicals, compared to nylon goods dyed withisomeric dyes.

Example 9.Dyeing with use of metal sequestering agent Deep-dyeable nylonyarn, as described by footnote 4, Table I, was dyed essentially asdescribed in footnote 1, Table I. That is, parts of deep-dyeable nylonyarn, 0.85 part of dodecyldiphenyl ether disulfonic acid, disodium salt(US. Pat. No. 2,081,876), 2 parts of monosodium phosphate, 0.5 part of anonionic surfactant, the condensation product of a C alcohol with 10moles of ethylene oxide, and- 0.2 part of dye of Example 2, No. 16 ofTable I, were added to 4000 parts water. The pH was adjusted to 6 withacetic acid and the temperature raised to 205210 F. This temperature wasmaintained for one hour, and the yarn then given a cold rinse.

A dyeing, as the above, was also made using 0.1 part of dye of Example3, dye 6 of Table I. These two dyeings served to provide the controls.

The influence of trace metals was determined by repeating the above twodyeings with 0.2 part of cupric sulfate.

The efiicacy of metal sequestering agents for reducing the metalsensitivity of the two dyes was determined by repeating the above twodyeings in the presence of 0.2 part cupric sulfate and 1 part Versene100 (a product disclosed to be ethylenediaminetetraacetic acidtetrasodium salt). The results obtained are given in Table IV asfollows:

TABLE IV.EFFECT OF Cu AND METAL SEQUESTERING ON TWO DYES USEFUL FORDEEP-DYEABLE Shade change Control Metal sensitivity Metal seques- Dye of(no Cu, tered (Ou+++ Example no Versene) (50 p.p.m. Cu) Versene 100 2Oontrol 54D 5-4 Br 3 d0.-. Very much duller 3 Br Example 10.Dyeingultra-deep-dyeable nylon The dyeing process described in Example 6 wasrepeated, using a multifiber BCF nylon yarn tufted onto a non-wovenpolypropylene backing, but consisting of four (4) bands. These includedthe three bands (a), (b) and (0), described in Example 6, with anadditional band (d), six ends in width, consisting of anultra-deep-dyeable nylon, 3700 denier, containing approximately 120 gramequivalents of free amine groups/10 grams of polymer, as described inUS. Pat. No. 3,078,248.

The carpet was bleached and dyed with the dye of Example 2, according tothe procedures in Example 6, care being taken to maintain the pH atabout 6 during the dyeing process.

The dye distribution on the four bands was estimated to be as follows:(a) 0%; (b) 5%; (c) 25%; (d) 70%. There was no discernible dullness ofshade on hand (d) versus band (0).

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom. The invention is not limited to the exact details shown anddescribed, for obvious modifications will occur to those skilled in theart.

What is claimed is:

1. In the aqueous process for dyeing textile materials comprised ofacid-dyeable polyamide fibers prepared from the condensation of adiamine with a dicarboxylic acid at a pH at about 3-7 and a temperatureof from 95 to 100 C. in a dye bath containing acid dyes and dyeingassistants, the imprvement consisting of using, as

said acid dyes, yellow-to-orange disazo dyes of the structure HO R;

wherein: A is selected from and SOaM

the M group in the latter structure being substituted in either aromaticring of the naphthalene nucleus;

R is selected from methyl, methoxy, NHCOCH C1 or Br;

n is an integer from 0 to 2;

M is selected from H, alkali metal or ammonium cation; 1 B is selectedfrom R is H and R is CH;,.

6. Claim 5 wherein the textile material is carpeting. 7. Claim 4 whereinA is l SOaNa R is H and R is CH;.;.

8. Claim 4 wherein A is s oaNa R is H and R is CH 9. Claim 8 whereinsaid dyebath also contains ethylenediaminetetraacetic acid tetrasodiumsalt;

21 22 10. Claim 3 wherein said dyebath has a temperature of ReferencesCited about 95-100 C. and contains ethylenediaminetetraace- D N tic acidtetrasodium salt; R is -CH;;; R is H; A is UNITE STATES FATE TS Selectedfrom 2,499,787 3/1950 Sharkey 821 B 5 FOREIGN PATENTS 1,201,549 7/1959lFrance 260186 N'r10aS- and 6- 1,365,903 5/1964 France 260-186 11,161,717 8/1969 Great Britain 8-21 B SOsNB 10 1,469,779 12/1968 Germanys 21 B OTHER REFERENCES Douglas, Adr, Feb. 19, 1957, pp. 122 to 125.Egli, Textilveredlung, Feb. 11, 1967, pp. 8566,

and B is selected from 15 GEORGE F. LESMES, Primary Examiner G and C P.C. IVES, Assistant Examiner 11. Claim 10 wherein said textile materialis poly- US (hexamethylene adipamide) carpeting. 2O 8- 2l B, 85; 260l84,186, 187, 190, 191

